Chemical Engineering Science, Vol.66, No.21, 5045-5054, 2011
Model-based scale-up of vacuum contact drying of pharmaceutical compounds
An integrated methodology for the scale-up of vacuum contact drying with intermittent agitation is described in this work. The methodology combines a mathematical model of vacuum contact drying, based on differential transient heat and energy balances, and a small-scale experimental apparatus for model validation and parameter estimation. The validated model was used for the estimation of drying times of six different pharmaceutical compounds at the pilot and manufacturing scale over a range of drying conditions - pressure 15-200 mbar, temperature 45-70 degrees C, solvents: acetone, water, methanol, n-propanol, and isopropyl acetate. The mean difference between predicted and actual drying times for the six compounds was less than 9%, which is considered a significant improvement over current semi-empirical approaches to vacuum contact drying scale-up. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.
Keywords:Drying;Heat transfer;Mass transfer;Mathematical modelling;Scale-up;Pharmaceutical processing